Association between Postprocedural Infarction and Antiplatelet Drug Resistance after Coiling for Unruptured Intracranial Aneurysms

The Impact of Preprocedural Platelet Function Testing on Periprocedural Complication Rates Associated With Pipeline Flow Diversion: An International Multicenter Study

BACKGROUND AND OBJECTIVES

Dual antiplatelet therapy (DAPT) is necessary to minimize the risk of periprocedural thromboembolic complications associated with aneurysm embolization using pipeline embolization device (PED). We aimed to assess the impact of platelet function testing (PFT) on reducing periprocedural thromboembolic complications associated with PED flow diversion in patients receiving aspirin and clopidogrel.

METHODS

Patients with unruptured intracranial aneurysms requiring PED flow diversion were identified from 13 centers for retrospective evaluation. Clinical variables including the results of PFT before treatment, periprocedural DAPT regimen, and intracranial complications occurring within 72 h of embolization were identified. Complication rates were compared between PFT and non-PFT groups. Differences between groups were tested for statistical significance using the Wilcoxon rank sum, Fisher exact, or χ 2 tests. A P -value <.05 was statistically significant.

RESULTS

580 patients underwent PED embolization with 262 patients dichotomized to the PFT group and 318 patients to the non-PFT group. 13.7% of PFT group patients were clopidogrel nonresponders requiring changes in their pre-embolization DAPT regimen. Five percentage of PFT group [2.8%, 8.5%] patients experienced thromboembolic complications vs 1.6% of patients in the non-PFT group [0.6%, 3.8%] ( P = .019). Two (15.4%) PFT group patients with thromboembolic complications experienced permanent neurological disability vs 4 (80%) non-PFT group patients. 3.7% of PFT group patients [1.5%, 8.2%] and 3.5% [1.8%, 6.3%] of non-PFT group patients experienced hemorrhagic intracranial complications ( P > .9).

CONCLUSION

Preprocedural PFT before PED treatment of intracranial aneurysms in patients premedicated with an aspirin and clopidogrel DAPT regimen may not be necessary to significantly reduce the risk of procedure-related intracranial complications.

Efficacy and Safety of Dual Antiplatelet Therapy with the Routine Use of Prasugrel for Flow Diversion of Cerebral Unruptured Aneurysms

PURPOSE

Prasugrel is not approved for patients treated with flow diverters, which have a high metal coverage ratio. However, robust antiplatelet therapy with prasugrel may prevent thromboembolic complications. We administered prasugrel and aspirin to all patients treated with flow diverters and reported the safety of the antiplatelet therapy regimen.

METHODS

This retrospective, single-center study evaluated the angiographic and clinical data of consecutive patients treated with flow diverters for cerebral unruptured aneurysms between June 2020 and May 2022. All patients received dual antiplatelet therapy, including prasugrel and aspirin. The administration of prasugrel ended 3 or 6 months after the procedure, whereas aspirin use continued for at least 12 months. Periprocedural complications (< 30 days post-procedure) and delayed complications (> 30 days post-procedure) were recorded.

RESULTS

During the study period, 120 unruptured aneurysms were treated with flow diverters in 110 patients. All patients, except one, survived longer than 12 months after the procedure. The rate of thromboembolic complications was 6.4%, and more than half of the patients had transient symptoms; one (0.9%) had a major ischemic stroke. One patient (0.9%) each had an asymptomatic, small subarachnoid hemorrhage and significant hemorrhagic complications with melena. The rate of permanent neurological deficits was 1.8%, and the mortality rate was 0.9%.

CONCLUSIONS

Dual antiplatelet therapy comprising routine use of prasugrel and aspirin for flow diverter-implanted patients possibly contributed to a low rate of thromboembolic complications and low risk of hemorrhagic complications.

Silent Embolic Infarction after Neuroform Atlas Stent-Assisted Coiling of Unruptured Intracranial Aneurysms

OBJECTIVE

There is still controversy regarding whether neck remodeling stent affects the occurrence of silent embolic infarction (SEI) after aneurysm coiling. Thus, the aim of the present study is to investigate the incidence of SEI after stent-assisted coiling (SAC) using Neuroform Atlas Stent (NAS) and possible risk factors. This study also includes a comparison with simple coiling group during the same period to estimate the impact of NAS on the occurrence of SEI.

METHODS

This study included a total of 96 unruptured intracranial aneurysms in 96 patients treated with SAC using NAS. Correlations of demographic data, aneurysm characteristics, and angiographic parameters with properties of SEI were analyzed. The incidence and characteristics of SEI were investigated in 28 patients who underwent simple coiling during the same period, and the results were compared with the SAC group.

RESULTS

In the diffusion-weighted imaging obtained on the 1st day after SAC, a total of 106 SEI lesions were observed in 48 (50%) of 96 patients. Of these 48 patients, 38 (79.2%) had 1-3 lesions. Of 106 lesions, 74 (69.8%) had a diameter less than 3 mm. SEI occurred more frequently in older patients (≥60 years, p=0.013). The volume of SEI was found to be significantly increased in older age (≥60 years, p=0.032), hypertension (p=0.036), and aneurysm size ≥5 mm (p=0.047). The incidence and mean volume of SEI in the SAC group (n=96) were similar to those of the simple coiling group (n=28) during the same period.

CONCLUSION

SEIs are common after NAS-assisted coiling. Their incidence in SAC was comparable to that in simple coiling. They occurred more frequently at an older age. Therefore, the use of NAS in the treatment of unruptured intracranial aneurysm does not seem to be associated with an increased risk of thromboembolic events if antiplatelet premedication has been performed well.

DWI-Detected Ischemic Lesions after Endovascular Treatment for Cerebral Aneurysms: An Updated Systematic Review and Meta-analysis

BACKGROUND AND PURPOSE

DWI-detected ischemic lesions are potential complications of endovascular procedures that are performed to treat intracranial aneurysms. We completed a systematic review and meta-analysis to identify the occurrence of DWI-detected ischemic lesions after endovascular treatment for intracranial aneurysms.

MATERIALS AND METHODS

A systematic literature search of PubMed, the Web of Science, EMBASE, and Scopus between January 2000 and June 2022 of post-endovascular procedures for intracranial aneurysm studies was conducted using the Nested Knowledge AutoLit software. The main outcome was DWI-detected ischemic lesions within 5 days of the procedures. Information regarding associated risk factors such as the type of procedure, patient demographics, and aneurysm characteristics was also collected.

RESULTS

Twenty-nine studies with 2686 patients were included. The overall incidence of DWI ischemic lesions was 47.0% (95% CI, 39.6%-55.8%). The highest rate of lesions was seen with flow diversion at 62.4% (95% CI, 48.4%-80.5%), followed by complex procedures at 49.3% (95% CI, 29.5%-82.1%), stent-assisted coiling at 47.5% (95% CI, 34.6%-65.3%), simple coiling at 47.1% (95% CI, 35.7%-62.3%), and balloon-assisted coiling at 37.0% (95% CI, 28.3%-48.4%). The differences among different techniques were not statistically significant; however, there was significant heterogeneity and a significant risk of publication bias among included studies.

CONCLUSIONS

Many patients who undergo endovascular procedures for intracranial aneurysms present with new postprocedural DWI-detected ischemic lesions, regardless of the endovascular procedure used. Future studies and meta-analyses are needed to investigate early and long-term outcomes of such small infarcts.

Trends in the Age of Patients Treated for Unruptured Intracranial Aneurysms from 1990 to 2020

BACKGROUND

The decision for treatment for unruptured intracranial aneurysms (UIAs) is often difficult. Innovation in endovascular devices have improved the benefit-to-risk profile especially for elderly patients; however, the treatment guidelines from the past decade often recommend conservative management. It is unknown how these changes have affected the overall age of the patients selected for treatment. Herein, we aimed to study potential changes in the average age of the patients that are being treated over time.

METHODS

A systematic search of the literature was performed to identify all studies describing the age of the UIAs that were treated by any modality. Scatter diagrams with trend lines were used to plot the age of the patients treated over time and assess the presence of a potential significant trend via statistical correlation tests.

RESULTS

A total of 280 studies including 83,437 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. Mean age of the patients was 55.5 years, and 70.7% were female. There was a significant increasing trend in the age of the treated patients over time (Spearman r: 0.250; P < 0.001), with a 1-year increase in the average age of the treated patients every 5 years since 1987.

CONCLUSIONS

The present study indicates that based on the treated UIA patient data published in the literature, older UIAs are being treated over time. This trend is likely driven by safer treatments while suggesting that re-evaluation of certain UIA treatment decision scores may be of great interest.

Periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for intracranial vertebral artery dissecting aneurysms

OBJECTIVE

The authors undertook an evaluation of periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for intracranial vertebral artery dissecting aneurysms (IVADAs) and assessed the relevant risk factors.

METHODS

The authors included a series of 195 patients who had undergone endovascular treatment for 198 IVADAs. Clinical data, morphological characteristics, treatment details, and periprocedural cerebrovascular complications including intraprocedural rupture, intraprocedural thrombosis, intracranial hemorrhage (ICH), transient ischemic attack (TIA), and ischemic stroke (IS) were recorded. After evaluation of the 30-day modified Rankin Scale (mRS) scores, the authors applied univariate and multivariate logistic regression analyses to identify the risk factors for complications and 30-day unfavorable clinical outcomes.

RESULTS

There were no intraprocedural ruptures, but the authors recorded intraprocedural thrombosis (n = 5), ICH (n = 3), TIA (n = 1), and IS (n = 13), comprising an 11.1% (22/198) complication rate. Multivariate logistic regression analysis indicated that hyperlipidemia (odds ratio [OR] 3.17, 95% confidence interval [CI] 1.20-8.41, p = 0.020), IS history (OR 5.55, 95% CI 1.46-21.01, p = 0.012), and subarachnoid hemorrhage (SAH) (OR 4.48, 95% CI 1.52-13.20, p = 0.007) were risk factors for overall complications, whereas aneurysmal height (OR 0.77, 95% CI 0.61-0.98, p = 0.032) was a protective factor. SAH (OR 6.44, 95% CI 1.54-26.89, p = 0.011) and preprocedural mRS score > 2 (OR 5.07, 95% CI 1.01-25.59, p = 0.049) were independent risk factors for perforator occlusion stroke. Periprocedural cerebrovascular complications (OR 32.09, 95% CI 3.00-343.94, p = 0.004) and preprocedural mRS score > 2 (OR 319.92, 95% CI 30.28-3379.98, p < 0.001) were independent risk factors for 30-day unfavorable clinical outcomes.

CONCLUSIONS

Hyperlipidemia, IS history, and SAH were independent predictors for overall periprocedural cerebrovascular complications of endovascular treatment for IVADAs, but aneurysmal height was an independent protective factor. SAH and preprocedural mRS score > 2 were independent risk factors for perforator occlusion stroke. Preprocedural mRS score > 2 and periprocedural complications were independent risk factors for 30-day unfavorable clinical outcomes.

Diffusion-weighted imaging lesions after endovascular treatment of cerebral aneurysms: A network meta-analysis

Background

Thromboembolism is one of the common complications in endovascular treatments including coiling alone, stent-assisted coiling (SAC), balloon-assisted coiling (BAC), and flow-diverting (FD) stents. Such treatments are widely used in intracranial aneurysms (IAs), which usually present as positive lesions in diffusion-weighted imaging (DWI). Whether these adjunctive techniques increase postprocedural DWI-positive lesions after endovascular treatment remains unclear.

Methods

A thorough electronic search for the literature published in English between January 2000 and October 2022 was conducted on PubMed, Medline, and EMBASE. Eighteen studies (3 cohort studies and 15 case-control studies) involving 1,843 patients with unruptured IAs (UIAs) were included. We performed a frequentist framework network meta-analysis (NMA) to compare the rank risks of cerebral thromboembolism of the above four endovascular treatments. The incoherence test was used to analyze the statistical disagreement between direct and indirect evidence. Funnel plots were used to analyze publication bias.

Results

The incidences of DWI lesions in patients who received FD stents, SAC, BAC, and coiling alone were 66.1% (109/165), 37.6% (299/795), 31.1% (236/759), and 25.6% (236/921). The incidence of DWI lesions in patients who received FD stents was higher than that in patients who received SAC [OR: 2.40; 95% CI (1.15, 5.00), P < 0.05], BAC [OR: 2.62; 95% CI (1.19, 5.77), P < 0.05], or coiling alone [OR: 2.77; 95% CI (1.26, 6.07), P < 0.05]. The incoherence test showed preferable consistency in this NMA. No obvious publication bias was found in the funnel plot.

Conclusion

FD stent placement brings more ischemic lesions identified by DWI than any other procedures for patients with UIA. The characteristics of FD stents may result in a high incidence of DWI lesions.

Predictors of thromboembolic complications after stent-assisted coiling of acutely ruptured intracranial aneurysms: A retrospective multicenter study

Background

Stent-assisted coiling (SAC) has been reported to safely and effectively treat wide-necked unruptured intracranial aneurysms. However, SAC of acutely ruptured aneurysms is controversial because of perioperative thromboembolic complications. We aimed to investigate the predictors of the thromboembolic complications after SAC of acutely ruptured aneurysms.

Methods

We performed a retrospective multicenter analysis of 110 consecutive patients with ruptured intracranial aneurysms treated with SAC within 72 h of the onset of subarachnoid hemorrhage. Thromboembolic complications were defined as any angiographic filling defects at the aneurysms base or the distal artery during the stent treatment and the new onset of symptomatic ischemia and a new hypo-density in a vascular distribution confirmed by CT scan within 24 h of treatment. These patients were grouped into patients with thromboembolic complications and those without thromboembolic complications. A multivariate logistic regression analysis was performed to identify predictors of thromboembolic complications.

Results

One hundred and one patients with 101 ruptured aneurysms were included in this study. 9 (8.9%) patients experienced thromboembolic complications. Patients with thromboembolic complications had a higher rate of unfavorable outcomes at discharge (P < 0.001) and at the last follow-up (p = 0.017). Of these patients, four patients presented with intraprocedural thrombus formation, and 5 experienced postprocedural ischemia. There was a trend toward thromboembolic complications in patients with a higher Fisher grade (p = 0.076) and those treated with intravenous tirofiban (p = 0.052). Patients with thromboembolic complications more often presented with poor grade clinical conditions (p = 0.005) and aneurysms with a large dome to neck ratio (p = 0.031). In the multivariate analysis, a worse World Federation World Federation of Neurological Societies (WFNS) grade (OR = 8.241; 95% CI 1.686–40.292; P = 0.009) and a larger dome to neck ratio (OR = 5.385; 95% CI 1.023–28.337; P = 0.047) were independent predictors of thromboembolic complications.

Conclusion

Patients with thromboembolic complications are more likely to have an unfavorable outcome. A worse clinical condition before the treatment and a larger dome to neck ratio were independent predictors of thromboembolic complications after SAC of acutely ruptured intracranial aneurysms.

Risk Factors for Recanalization after Coil Embolization

The aim of our study was to identify risk factors for recanalization 6 months after coil embolization using clinical data followed by computational fluid dynamics (CFD) analysis. Methods: Firstly, clinical data of 184 patients treated with coil embolization were analyzed retrospectively. Secondly, aneurysm models for high/low recanalization risk were generated based on ROC curves and their cut-off points. Afterward, CFD was utilized to validate the results. Results: In multivariable analysis, aneurysm filling during the first embolization was an independent risk factor whilst packing density was a protective factor of recanalization after 6 months in patients with aSAH. For patients with unruptured aneurysms, packing density was found to be a protective factor whilst the aneurysm neck size was an independent risk factor. Complex flow pattern and multiple vortices were associated with aneurysm shape and were characteristic of the high recanalization risk group. Conclusions: Statistical analysis suggested that there are various factors influencing recanalization risk. Once certain values of morphometric parameters are exceeded, a complex flow with numerous vortices occurs. This phenomenon was revealed due to CFD investigations that validated our statistical research. Thus, the complex flow pattern itself can be treated as a relevant recanalization predictor.

Clopidogrel response predicts thromboembolic events associated with coil embolization of unruptured intracranial aneurysms: A prospective cohort study

Objective

Periprocedural thromboembolic events are a serious complication associated with coil embolization of unruptured intracranial aneurysms. However, no established clinical rule for predicting thromboembolic events exists. This study aimed to clarify the significance of adding preoperative clopidogrel response value to clinical factors when predicting the occurrence of thromboembolic events during/after coil embolization and to develop a nomogram for thromboembolic event prediction.

Methods

In this prospective, single-center, cohort study, we included 345 patients undergoing elective coil embolization for unruptured intracranial aneurysm. Thromboembolic event was defined as the occurrence of intra-procedural thrombus formation and postprocedural symptomatic cerebral infarction within 7 days. We evaluated preoperative clopidogrel response and patients’ clinical information. We developed a patient-clinical-information model for thromboembolic event using multivariate analysis and compared its efficiency with that of patient-clinical-information plus preoperative clopidogrel response model. The predictive performances of the two models were assessed using area under the receiver-operating characteristic curve (AUC-ROC) with bootstrap method and compared using net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

Results

Twenty-eight patients experienced thromboembolic events. The clinical model included age, aneurysm location, aneurysm dome and neck size, and treatment technique. AUC-ROC for the clinical model improved from 0.707 to 0.779 after adding the clopidogrel response value. Significant intergroup differences were noted in NRI (0.617, 95% CI: 0.247–0.987, p < .001) and IDI (0.068, 95% CI: 0.021–0.116, p = .005).

Conclusions

Evaluation of preoperative clopidogrel response in addition to clinical variables improves the prediction accuracy of thromboembolic event occurrence during/after coil embolization of unruptured intracranial aneurysm.

Antiplatelet Drugs for Neurointerventions: Part 2 Clinical Applications

Endovascular techniques have expanded to include balloon and stent-assistance, flow diversion and individualized endovascular occlusion devices, to widen the treatment spectrum for more complex aneurysm morphologies. While usually well-tolerated by patients, endovascular treatment of intracranial aneurysms carries the risk of complications, with procedure-related ischemic complications being the most common. Several antiplatelet agents have been studied in a neurointerventional setting for both prophylaxis and in the setting of intraprocedural thrombotic complications. Knowledge of these antiplatelet agents, evidence for their use and common dosages is important for the practicing neurointerventionist to ensure the proper application of these agents.Part one of this two-part review focused on basic platelet physiology, pharmacology of common antiplatelet medications and future directions and therapies. Part two focuses on clinical applications and evidence based therapeutic regimens.

Mechanically Induced Vasospasm and Postoperative Cerebral Infarction after Coil Embolization of Unruptured Cerebral Aneurysms in Anterior Circulation

We occasionally encounter situations which requires retraction of the guiding system or administration of vasodilatory agents for mechanically induced vasospasm (MVS). However, whether MVS is associated with postoperative cerebral infarction has not been reported.To explore factors associated with MVS and to verify how MVS influences procedure outcomes,we reviewed consecutive cases of unruptured aneurysms in the anterior circulation treated with coil embolization between January 2017 and February 2020. Collected data included patients' clinical characteristics, devices, vessel tortuosity, severity of MVS, diameter of the parent vessel, and procedure duration. Significant MVS was defined as a condition necessitating a pause in the procedure. We also counted postoperative diffusion-weighted imaging (DWI) hyperintense spots (DHS). Parameters associated with MVS and postoperative DHS were investigated by multivariate logistic regression.A total of 103 cases met the eligibility criteria, with significant MVS occurring in 21 cases (20.3%), and postoperative DHS (≥3) confirmed in 30 cases (29.1%). Significant MVS was associated only with larger caliber at the tip of the guiding system compared with the parent vessel (p = 0.001). Postoperative DHS was associated with significant MVS (p = 0.002, OR: 5.313; 95% CI: 1.851-15.254).Significant MVS is a predictor of postoperative cerebral ischemia and occurs in patients with smaller caliber of the parent vessel. In patients with high-risk features for MVS, we should avoid navigating the guiding system forcibly through the narrow parent vessel. In other words, it is crucial to place the large-caliber guiding sheath/catheter proximally and only guide distally the intermediate catheter with better trackability.

Delayed thromboembolic events after coiling of unruptured intracranial aneurysms in a prospective cohort of 335 patients

BACKGROUND

Coiling is the first-line treatment for the management of unruptured intracranial aneurysms (UIAs), but delayed thromboembolic events (TEEs) can occur after such treatment. ARETA (Analysis of Recanalization after Endovascular Treatment of Intracranial Aneurysm) is a prospective multicenter study conducted to analyze aneurysm recanalization. We analyzed delayed TEEs in the UIA subgroup.

METHODS

Sixteen neurointerventional departments prospectively enrolled patients treated for ruptured and unruptured aneurysms between December 2013 and May 2015. Participant demographics, aneurysm characteristics, and endovascular techniques were recorded. Data were analyzed from participants with UIA treated by coiling or balloon-assisted coiling. We assessed the rates, timing, management, clinical outcomes, and risk factors for delayed TEEs using univariable and multivariable analyses.

RESULTS

The rate of delayed TEEs was 2.4% (95% CI 1.0% to 4.6%) in patients with unruptured aneurysms, with all events occurring in the week following the procedure. In multivariate analysis, two factors were associated with delayed TEEs: autosomal dominant polycystic kidney disease (ADPKD): 20.0% in patients with ADPKD vs 1.9% in patients without ADPKD (OR 27.3 (95% CI 3.9 to 190.2), p=0.0008) and post-procedure aneurysm remnant: 9.4% in patients with post-procedure aneurysm remnant vs 1.6% in patients with adequate occlusion (OR 9.9 (95% CI 1.0 to 51.3), p=0.006). We describe modalities of management as well as clinical outcomes.

CONCLUSIONS

Delayed TEE is a relatively rare complication after coiling of UIAs. In this series, all occurred in the week following the initial procedure. Two factors were associated with delayed TEE: ADPKD and aneurysm remnant at procedure completion.

CLINICAL TRIAL REGISTRATION

NCT01942512.

Factors Associated with Procedural Thromboembolisms after Mechanical Thrombectomy for Acute Ischemic Stroke

Background and objective: Procedural thromboembolisms after mechanical thrombectomy (MT) for acute ischemic stroke has rarely been studied. We retrospectively evaluated factors associated with procedural thromboembolisms after MT using diffusion-weight imaging (DWI) within 2 days of MT. Materials and Methods: From January 2018 to March 2020, 78 patients with acute ischemic stroke who underwent MT were evaluated using DWI. Procedural thromboembolisms were defined as new cerebral infarctions in other territories from the occluded artery on DWI after MT. Results: Procedural thromboembolisms were observed on DWI in 16 patients (20.5%). Procedural thromboembolisms were associated with old age (73.8 ± 8.18 vs. 66.8 ± 11.2 years, p = 0.021), intravenous (IV) thrombolysis (12 out of 16 (75.0%) vs. 25 out of 62 (40.3%), p = 0.023), heparinization (4 out of 16 (25.0%) vs. 37 out of 62 (59.7%), p = 0.023), and longer procedural time (90.9 ± 35.6 vs. 64.4 ± 33.0 min, p = 0.006). Multivariable logistic regression analysis revealed that procedural thromboembolisms were independently associated with procedural time (adjusted odds ratio (OR); 1.020, 95% confidence interval (CI); 1.002–1.039, p = 0.030) and IV thrombolysis (adjusted OR; 4.697, 95% CI; 1.223–18.042, p = 0.024). The cutoff value of procedural time for predicting procedural thromboembolisms was ≥71 min (area under the curve; 0.711, 95% CI; 0.570–0.851, p = 0.010). Conclusions: Procedural thromboembolisms after MT for acute ischemic stroke are significantly associated with longer procedural time and IV thrombolysis. This study suggests that patients with IV thrombolysis and longer procedural time (≥71 min) are at a higher risk of procedural thromboembolisms after MT for acute ischemic stroke.

The Effect of Ticagrelor on Platelet Reactivity in Patients with Clopidogrel Resistance Undergoing Neuroendovascular Procedures

BACKGROUND AND PURPOSE

Suboptimal platelet inhibition by clopidogrel (clopidogrel resistance) may be associated with high rates of stent thrombosis and ischemic events. Our objective was to determine if ticagrelor, a P2Y₁₂ receptor inhibitor, can result in platelet inhibition in patients with clopidogrel resistance.

METHODS

A thromboelastography-platelet mapping assay was used in all patients undergoing neuroendovascular procedures requiring oral clopidogrel. In patients with suboptimal platelet inhibition (<60%) on clopidogrel, ticagrelor was imitated after an oral bolus of 180 mg followed by 90 mg twice daily and the platelet mapping assay was repeated. The primary endpoint was hemorrhagic complications classified as major (hemoglobin decrease >5 g/dL or intracranial hemorrhage with deficits), minor (hemoglobin decrease 3-5 g/dL or intracranial hemorrhage without residual deficits), or insignificant.

RESULTS

Suboptimal platelet inhibition on clopidogrel was seen in 70 of 106 patients undergoing neuroendovascular procedures. There was a significantly higher magnitude of platelet inhibition with ticagrelor compared with clopidogrel in patients with clopidogrel resistance (mean ± SD: 85.90 ± 10.74% vs. 29.26 ± 17.71%; P < .001); 50 of 70 patients showed optimal inhibition. Two patients had major (fatal) hemorrhagic events (both received either intravenous thrombolytics and/or eptifibatide infusion). Three patients had minor hemorrhagic events, and two patients had insignificant hemorrhagic events. Four of seven hemorrhagic events occurred in patients with optimal response to clopidogrel, two occurred in patients with suboptimal response to ticagrelor, and one occurred in a patient with optimal response to ticagrelor.

CONCLUSIONS

Oral ticagrelor can augment platelet inhibition in patients who have clopidogrel resistance.

Antiplatelet therapy for prevention of thromboembolic complications in coiling-only procedures for unruptured brain aneurysms

BACKGROUND AND PURPOSE

Thromboembolic events are recognized complications of aneurysm coiling.

OBJECTIVE

To identify any protective effects of antiplatelet therapy use before coiling of unruptured aneurysms.

METHODS

We conducted a meta-analysis of clinical studies published up to February 2019. We included studies reporting symptomatic thromboembolic events (defined as clinical stroke or transient ischemic attacks) in patients who received antiplatelet therapy before coiling of unruptured aneurysms using unassisted coiling, balloon assistance, or multiple microcatheters. We excluded ruptured aneurysms and those treated with stent coiling or flow diverters.

RESULTS

We identified 14 studies (2486 patients). All were single-center studies and four were prospective. In three studies with a control (no treatment) arm, the pooled risk ratio for symptomatic thromboembolic events with versus without antiplatelet therapy was 0.33 (95% CI 0.17 to 0.92, p= 0.035). The cumulative risk of symptomatic thromboembolic events with single antiplatelet agents was 5.0% '56/1122' (95% CI 1.6% to 8.4%, I²83.63%), and with dual or multiple agents 2.7% '33/1237' (95% CI 1.0% to 3.0%, I²39.9%). The incidence of diffusion lesions was reported in seven studies. It was 50.5% '96/190' (95% CI 7.3% to 93.9%, I²94.4%) with single agents compared with 43.9% '196/446' (95% CI 25.9% to 61.9%, I²73.4%) with dual or multiple agents.

CONCLUSION

Periprocedural antiplatelet therapy was associated with a low symptomatic thromboembolic event after coiling-only for unruptured aneurysms. However, available evidence is of limited quality with significant heterogeneity, requiring evidence from randomized controlled trials.

Efficacy and safety of prasugrel therapy for intracranial aneurysms with endovascular treatment: A meta-analysis

BACKGROUND

Prasugrel as a second generation P2Y12 adenosine diphosphate receptor antagonist which in the cerebral aneurysms with Endovascular treatment have become more emphasized.

OBJECTIVE

To compare the efficacy and safety of prasugrel therapy for intracranial aneurysms with endovascular treatment.

METHODS

The databases of PubMed, Embase, Cochrane Library databases and China Biology Medicine disc were retrieved with computers for collecting controlled trials about the comparison in the efficacy and safety of prasugrel and clopidogrel published from inception to September 2018. At the same time, the reference materials of included literature were retrieved manually. After rigorous evaluation on literature quality, the eligible data of the trials was extracted and given a Meta-analysis by applying RevMan5.3 software.

RESULTS

Of the 96 studies identified, 7 trials were included. Results of meta-analysis showed that compared with patients receiving clopidogrel treatment, novel platelet P2Y₁₂ receptor inhibitor prasugrel were effective in reducing the incidence of thromboembolic events (OR = 0.19, 95%CI: 0.08-0.45, P = .0001), but did not increase the risk of hemorrhagic complication (OR = 1.00, 95%CI: 0.53-1.89, P = 1.00), and the PRU (OR = 0.19, 95%CI: 0.08-0.45, P = .0001) and Percentage inhibition of platelet (MN = 37.05, 95%CI: 33.37-40.73, P < .00001) were controlled in a better range.

CONCLUSION

In antiplatelet therapy after aneurysmal interventional therapy, the second generation of P2Y₁₂ adenosine receptor antagonist prasugrel can significantly reduce the risk of thrombosis without increasing the risk of bleeding.

Microhemorrhagic transformation of ischemic lesions on T2*-weighted magnetic resonance imaging after Pipeline embolization device treatment

OBJECTIVE

The authors sought to demonstrate that hemorrhagic transformation of ischemic lesions is the main cause of delayed intracerebral hemorrhage (ICH) after Pipeline embolization device (PED) treatment and to estimate the rate of hemorrhagic transformation of new postprocedure ischemic lesions.

METHODS

Patients who underwent PED placement (PED group) from November 2015 to March 2017 or stent-mediated embolization (EN group) from December 2010 to October 2015 were retrospectively analyzed. Pre- and postprocedural MR images and 6-month follow-up MR images for each patient were scored for the presence of postprocedural bland ischemic and hemorrhagic lesions using diffusion-weighted MRI (DWI) and T2*-weighted MRI (T2*WI), respectively.

RESULTS

The PED group comprised 28 patients with 30 intracranial aneurysms, and the EN group comprised 24 patients with 27 intracranial aneurysms. The mean number of ischemic lesions on DWI 1 day postprocedure was higher in the PED group than in the EN group (5.2 vs 2.7, p = 0.0010). The mean number of microbleeds detected on T2*WI 6 months postprocedure was higher in the PED group than in the EN group (0.6 vs 0.15, p = 0.028). A total of 36.7% of PED-treated patients exhibited new microbleeds on T2*WI at 6 months postprocedure, with at least 77.8% of these lesions representing hemorrhagic transformations of the new ischemic lesions observed on day 1 postprocedure. The rate of adjunctive coil embolization (27.3% vs 0.0%, p = 0.016) and the mean number of ischemic lesions observed 1 day postprocedure (6.6 vs 4.3, p = 0.020) were predictors of subsequent microbleeds in the PED group.

CONCLUSIONS

New microbleeds detected using T2*WI at 6 months postprocedure were more common after PED treatment than after stent-mediated embolization. Approximately three-quarters of these lesions were hemorrhagic transformations of new ischemic lesions observed on day 1 postprocedure. Prevention of intraprocedural or postprocedural infarcts is necessary to reduce the risk of hemorrhagic complications following PED placement.

Clopidogrel Response Variability in Unruptured Intracranial Aneurysm Patients Treated with Stent-Assisted Endovascular Coil Embolization : Is Follow-Up Clopidogrel Response Test Necessary?

Objective

The purpose of this study was to analyze the variability of clopidogrel responses according to duration of a clopidogrel drug regimen after stent-assisted coil embolization (SAC), and to determine the correlation between the variability of clopidogrel responses and thromboembolic or hemorrhagic complications.

Methods

A total of 47 patients who underwent SAC procedures to treat unruptured intracranial aneurysms were enrolled in the study. Preoperatively, patients received more than seven days of aspirin (100 mg) and clopidogrel (75 mg), daily. P2Y12 reaction unit (PRU) was checked with the VerifyNow test one day before the procedure (pre-PRU) and one month after the procedure (post-PRU). PRU variability was calculated as the difference between the initial response and the follow-up response. Patients were sorted into two groups based on their response to treatment : responsive and hypo-responsive.

Results

PRU variability was significantly greater in the hypo-responsive group when compared to the responsive group (p=0.019). Pre-PRU and serum platelets counts were significantly correlated with PRU variation (p=0.005 and p=0.004, respectively). Although thromboembolic complication had no significant correlated factors, hemorrhagic complication was correlated with pre-PRU (p=0.033).

Conclusion

In conclusion, variability of clopidogrel responses during clopidogrel medication was correlated to serum platelet counts and the initial clopidogrel response. Thromboembolic and hemorrhagic complications did not show correlation with the variability of clopidogrel response, or the clopidogrel response after one month of medication; however, hemorrhagic complication was associated with initial clopidogrel response. Therefore, it is recommended to test patients for an initial clopidogrel response only, as further tests would be insignificant.

Relationship between adverse events and antiplatelet drug resistance in neurovascular intervention: a meta-analysis

Background

This meta-analysis aimed to evaluate the association between antiplatelet resistance and the risk of procedure-related complications in neurovascular interventions.

Methods

We identified relevant articles by searching electronic databases and reviewed the reference lists of selected papers. The risk of adverse events between antiplatelet responders and hyporesponders during neurointervention was compared in eligible clinical studies. Risk ratios (RRs) and 95% CIs were pooled using a random-effects meta-analysis.

Results

Of 2134 potentially relevant studies, our search identified 15 studies enrolling a total of 2365 patients. Pooled RRs showed thromboembolic events (TEE) were more frequent in hyporesponders (RR 2.634, 95% CI 1.465 to 4.734). However, hemorrhagic complications did not differ between the two groups (RR 1.236, 95% CI 0.642 to 2.380). In subgroup analysis, hyporesponders showed a higher prevalence of TEE with standard antiplatelet medication, but there was no obvious difference in TEE between the two arms when using a modified antiplatelet medication (RR 3.645, 95% CI 1.537 to 8.646; and RR 1.877, 95% CI 0.749 to 4.751). Studies using stent placement for aneurysms showed a higher TEE rate in hyporesponders (RR 3.221, 95% CI 1.899 to 5.464).

Conclusion

Antiplatelet resistance was significantly associated with TEE in neurointervention, and this adverse event was associated with individually-intensified antiplatelet medication as well as the type of neurointerventional procedure. Our findings support the use of antiplatelet resistance assays and tailored antiplatelet medications in neurovascular stent placement as a management strategy to reduce thromboembolic risk.

Antiplatelet Premedication for Stent-Assisted Coil Embolization of Intracranial Aneurysms: Low-Dose Prasugrel vs Clopidogrel

BACKGROUND

The use of antiplatelet medications to prevent thrombosis in the treatment of cerebral aneurysms with stents has become widely emphasized.

OBJECTIVE

To compare low-dose prasugrel with clopidogrel in stent-assisted coil embolization of intracranial aneurysms.

METHODS

This is a retrospective review of 311 aneurysms from 297 patients who underwent stent-assisted endovascular coil embolization of unruptured intracranial aneurysm between November 2014 and March 2017. Thromboembolic and hemorrhagic adverse events were compared between 207 patients who received low-dose prasugrel (PSG group) and 90 patients who received clopidogrel (CPG group).

RESULTS

P2Y12 reaction unit (PRU) values were significantly lower in the PSG group (PSG group vs CPG group, 132.3 ± 76.9 vs 238.1 ± 69.1; P &lt; .001); the percentage of inhibition was also statistically higher in the PSG group (54.0 ± 26.0% vs 20.8 ± 18.6%; P &lt; .001). Thromboembolic events occurred less frequently in the PSG group than in the CPG group (0.9% vs 6.4%; P = .01), whereas there was no significant difference in the percentage of hemorrhagic complications (0.5% vs 2.2%; P = .22). In the multivariate analysis, clopidogrel as the antiplatelet medication was the sole significant risk factor for thromboembolism in this series of patients undergoing stent-assisted coil embolization.

CONCLUSION

Use of low-dose PSG as an antiplatelet premedication is quick, effective, and safe for stent-assisted coil embolization of unruptured intracranial aneurysms. Prasugrel premedication significantly lowered the frequency of thromboembolic events without increasing the risk of hemorrhage.

Diffusion-Weighted Imaging-Detected Ischemic Lesions following Endovascular Treatment of Cerebral Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Endovascular treatment of intracranial aneurysms is associated with the risk of thromboembolic ischemic complications. Many of these events are asymptomatic and identified only on diffusion-weighted imaging. We performed a systematic review and meta-analysis to study the incidence of DWI positive for thromboembolic events following endovascular treatment of intracranial aneurysms.

MATERIALS AND METHODS

A comprehensive literature search identified studies published between 2000 and April 2016 that reported postprocedural DWI findings in patients undergoing endovascular treatment of intracranial aneurysms. The primary outcome was the incidence of DWI positive for thromboembolic events. We examined outcomes by treatment type, sex, and aneurysm characteristics. Meta-analyses were performed by using a random-effects model.

RESULTS

Twenty-two studies with 2148 patients and 2268 aneurysms were included. The overall incidence of DWI positive for thromboembolic events following endovascular treatment was 49% (95% CI, 42%-56%). Treatment with flow diversion trended toward a higher rate of DWI positive for lesions than coiling alone (67%; 95% CI, 46%-85%; versus 45%; 95% CI, 33%-56%; P = .07). There was no difference between patients treated with coiling alone and those treated with balloon-assisted (44%; 95% CI, 29%-60%; P = .99) or stent-assisted (43%; 95% CI, 24%-63%; P = .89) coiling. Sex, aneurysm rupture status, location, and size were not associated with the rate of DWI positive for lesions.

CONCLUSIONS

One in 2 patients may have infarcts on DWI following endovascular treatment of intracranial aneurysms. There is a trend toward a higher incidence of DWI-positive lesions following treatment with flow diversion compared with coiling. Patient demographics and aneurysm characteristics were not associated with DWI-positive thromboembolic events.

Prophylactic Antiplatelet Medication in Endovascular Treatment of Intracranial Aneurysms: Low-Dose Prasugrel versus Clopidogrel

BACKGROUND AND PURPOSE

Prophylactic antiplatelet medication is beneficial in decreasing thromboembolic complications during endovascular treatment of unruptured intracranial aneurysms. The efficacy may be limited by variability of individual response to antiplatelet medication, especially clopidogrel. We compared the efficacy of 2 antiplatelet medications, low-dose prasugrel and clopidogrel, in patients undergoing endovascular treatment of unruptured aneurysms.

MATERIALS AND METHODS

From November 2014 to July 2015, 194 patients with a total of 222 unruptured aneurysms underwent endovascular treatment at a single institution. Laboratory and clinical data from the prospectively maintained registry were used in this study. Antiplatelet medication was given the day before endovascular treatment (prasugrel 20 mg or 30 mg or clopidogrel 300 mg). Response to the antiplatelet medication was measured by the VerifyNow system. Periprocedural adverse event rates between the 2 groups were compared.

RESULTS

There were no significant differences in the baseline characteristics of patients and aneurysms between the 2 groups. The P2Y12 reaction unit values were lower (clopidogrel group versus prasugrel group, 242.7 ± 69.8 vs 125.7 ± 79.4; P < .0001) and percentage inhibition values were higher (22.1% ± 19.7% vs 60.2 ± 24.7%; P < .0001) in the prasugrel group. There were no thromboembolic events, but there was 1 procedural bleed in each group, without any clinical consequences.

CONCLUSIONS

The prasugrel group showed more effective and consistent platelet inhibition. We may omit the antiplatelet response assay with the low-dose prasugrel premedication before the endovascular treatment of patients with unruptured aneurysms. Further study is required to determine whether there is benefit of this strategy regarding clinical outcome.